Establishment of rabbit femoral 3D biomechanical models

Zhixiang LI; Chunlin ZHANG

ABSTRACT

BACKGROUND:

The image edge of rabbit femur is identified using self-programmed Matlab program. But owing to the complexity of the model, can we set up a femoral structure model after the solid model of the femur created in UG three-dimensional (3D) software is put into ANSYS software?

OBJECTIVE:

To explore the method of constructing 3D biomechanical model of rabbit femur.

DESIGN:

Randomized controlled observation.

SETTING:

Biomechanics Laboratory of Beijing Institute of Technology.

MATERIAL:

One 1-year-old female New Zealand white rabbit weighing 2.6 kg. ACTIS 400/225 industry CT scanner (BIR,USA).

METHODS:

The experiment was performed at the Biomechanics Laboratory of Beijing Institute of Technology from July to transformed into *.bmp format. Photoshop image processing software was applied for some essential processing on the original image, such as contrast control, smoothing and noise attenuation to strengthen the differentiability and analyzability of the image. In addition, the magnetic noose tool was used to outline the contour line of inside and outside boundary, and obtain the inside and outside contour line of every layer of the femur. The rabbit femur was scanned by industry CT starting from the upper extreme of the femur, vertical to femoral ordinate axis line (slice space=I ram). The scanning slice space was adjusted to 2 mm from the 43rd layer below small trochanter to the 53ra layer of middle femur because the shape between these layers was relatively regular. Totally 87 slices of layer images were scanned 9.9 cm in length. The image was put into the computer and processed to get the boundary contour line; the contour line coordinate for modeling was obtained through imported from UG into ANSYS software. A solid model of the femur was produced automatically. Finally, the solid model with cavity was obtained using subtraction option of Boolean in ANSYS.MAIN OUTCOME

MEASURES:

Establishment of rabbit femoral structure model. connected by the multiple valid points was formed. The 2nd, 3rd, 4th until the 87th layers were read in turn, and the inside and automatically divide the mesh to produce finite element meshes and 42 221 nodes and 27 768 elements were obtained.

CONCLUSION:

The 3D model of rabbit femur actually simulated the anatomic appearance of the femur. This model lays a foundation for identifying the optimal parameter of vibration that can improve bone mineral density by finite element analysis.